UnlockR is a free and open source pdf password remover application for Linux and Windows. Using this UnlockR app, you can remove passwords from all your PDF files. It is a simple PDF decrypt application and comes with a easy to use UI. It is released under GNU General Public License v3.0.
How to Install UnlockR on Ubuntu Linux
To install unlockR app on your Linux system, you need flatpak and flathub on your system. If you don’t have then first install flatpak and flathub on your system and restart it after the installation.
sudo apt install flatpak
flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
After that open the terminal app (crl+alt+t) and run below UnlockR flatpak install command.
flatpak install flathub com.github.jkotra.unlockr
And open it using below command.
flatpak run com.github.jkotra.unlockr
How to Remove Password from PDF
Now open the password protected pdf file using the Choose a File. Now type the PDF file password and click the Decrypt.
It will remove password from that file and you will get new decrypted (password removed ) file in your Documents folder.
You can also uninstall it using below command.
flatpak uninstall com.github.jkotra.unlockr
sudo flatpak uninstall com.github.jkotra.unlockr